There is an overwhelming case against convicted police killer David Eastman and he should not be let out of jail, the lawyer for ACT prosecutors says.

Jeremy Kirk, counsel for the ACT director of public prosecutions (DPP), said Eastman's conviction for the 1989 murder of Australian Federal Police assistant commissioner Colin Winchester should be confirmed.

This follows the release of the report of the long-running inquiry into Eastman's conviction, in which former Northern Territory chief justice Brian Martin found there was a substantial miscarriage of justice at his 1995 trial.

He recommended Eastman's conviction be quashed and a pardon granted.

It is now up to the ACT supreme court to decide how to proceed, with the full bench of three judges hearing submissions from the DPP, police and from Eastman.

Justice Martin found key forensic evidence used in the trial to be discredited.

That relates to gunshot residue at the murder scene and tiny particles found in the boot of Eastman's car, which supposedly matched.

But even without that evidence there was a strong circumstantial case against Eastman, Kirk said.

He had made threats to Winchester. Although the murder weapon, a .22 calibre Ruger rifle was not found, there was clear evidence linking it to Eastman.

As well, Eastman was unable to account for his movements at the time of the murder when questioned by two detectives the following day.

Kirk said it was entirely implausible that Eastman, a demonstrably intelligent man, could not explain what he was doing the night before and that was strongly suggestive of guilt.

Looking at the totality of the evidence, there was an overwhelming case against Eastman, he said.

Kirk said if the court quashed the conviction, it should order a retrial, although after 25 years, there was no guarantee that would ever happen.

The hearing resumes on Thursday when Eastman's council presents his argument for the verdict to be quashed and for his client to be released.